A variety of multi-level electrical interconnection systems are known. Elwell et al U.S. Pat. No. 5,412,539 discloses a circuit having raised features, and a dielectric decal layer overlying the circuit. The decal layer has preformed holes extending therethrough and aligned with the raised features. A second circuit layer overlies the decal and includes contact pads overlying one of the preformed holes in the decal and the raised feature. Silver epoxy is used to make electrical connection between the raised feature on the first circuit layer and the contact pad on the second circuit layer.
Other similar systems are known. One such system includes a dielectric decal layer having preformed holes extending therethrough and an additional adhesive decal layer. The adhesive layer also has preformed holes to receive a raised feature of a first circuit layer. A second circuit layer overlies the adhesive decal and includes contact pads aligned with the raised features. The steps of forming holes in the dielectric and adhesive layers and aligning the holes with raised features all add cost to the overall system.
The present invention provides alternatives to and advantages over the prior art.